Apparatus for hot pressing powdered metals



May 27, 1952 D. RICHARDSON, SR

APPARATUS FOR HOT-PRESSING POWDERED METALS 4 Sheets-Sheet 1 Original Filed Oct. 17, 1945 HIGH PRIQUEKY I I. ECTIIM L 4 ENERGY INVENTOR LLOYD D. R ICHA RDSON, 5R.

ATTORNEYJ May 27, 1952 D. RICHARDSON, SR

APPARATUS FOR HOT-PRESSING POWDERED METALS Original Filed Oct. 1'7, 1945 4 Sheets-Sheet 2 LLOYD nl'ucumnsomsn pv W y 1952 1.. D. RICHARDSON, SR 2,598,015

APPARATUS FOR HOT-PRESSING POWDERED METALS Original Filed Oct. 17, 1945 4 Sheets-Sheet 5 T /////Jg INVENOR LLOYD P RICHARDSON, SR.

Arromvsvs L. D. RICHARDSON, SR

APPARATUS FOR HOT-PRESSING POWDERED METALS May 27, 1952 4 Sheets-Sheet 4 Original Filed Oct. 1'7, 1945 ILOYD D. RICHHRDSOMSR.

A Tra Run:

Patented May 27, 1952 APPARATUS FOR HOT PRESSING POWDERED METALS Lloyd D. Richardson, Sr., Spring Valley, Ohio, assignor to H-P-M Development Corporation, Mount Gilead, Ohio, a corporation of Delaware Substituted for application Serial No. 622,743, October 17, 1945. This application April 17, 1950, Serial No. 156,418

5 Claims.

This application is a substitute application for my prior forfeited application Serial Number 622,743, filed October 17, 1945, entitled Method and Apparatus for Hot Pressing.

This invention relates to apparatus for form ing workpieces from powdered materials, at least a portion of which is metallic, and particularly refers to the hot forming of such materials.

The usual method of forming workpieces from powdered metals requires that the powdered material first be compacted into the configuration of the workpiece and thereafter heated to sintering temperature in a separate oven. This manner of producing the workpieces requires additional machine work following the sintering b cause of the shrinkage which takes place in the sintering oven. Also, two complete machines are required, one for shaping the workpiece and the other for sintering.

The principal object of this invention is to pro-- vide apparatus in which compacts of the material to be worked are preheated adjacent the pressing station and are continuously fed thereto, whereby completed workpieces result when the heated compact is pressed.

It is a further object of this invention to provide apparatus for hot working briquettes or compacts of granulated materials into workpieces, starting with the cold briquette or compact and finishing with a completed workpiece.

It is still another object to provide apparatus for receiving cold briquettes, andheating the briquettes to working temperature, and for working the heated briquettes into shape, these steps being carried out in a reducing atmosphere.

These and other objects and advantages will become more apparent upon reference to the accompanying drawings, in which:

Fig. 1 is an elevational view showing an apparatus constructed according to this invention;

Fig. 2 is a plan view of the device shown in Fig. 1;

Figs. 3, 4, 5, and 6 are views illustrating the apparatus in various stages during a pressing cycle; and

Figs. 7, 8, 9, and 10 are views 01" a modified construction in various stages of a pressing cycle. Referring to the drawings, and particularly to Figs. 1-6, there is illustrated a, press comprising a bed I 0 which rctatably mounts a turret l 2 that is driven in its indexing movements by a motor l4 through the pinion and rack arrangement at "3.

The turret carries a plurality of die cells IS, in this case, four, which are adapted successively 2 to register with a heating station at 2B and thereafter with a pressing station at 22.

Connected with the bed [0 by the strain rods 24 and nuts 26 is a press head-28 which supports the cylinder 30 of the pressing station. The head 23 likewise supports the sleeve 32 of the heating station 2! As will be seen in Fig. 3, the heating station comprises a sleeve of electrical insulating material about which is arranged a coil 34 which may be selectively connected with a source of igh frequency electrical energy 36 by means of a switch 38.

In opposed relationship to the pressing station 22, and on the other side of the turret therefrom, is a motor 40 within which is reciprocable the plunger 42 that forms a bottom for the die cells as they are moved into pressing position and have a workpiece operated therein. The motor 40 is preferably fluid operable and is controlled in its movements by a valve 44.

Reciprocable within the cylinder 30 of the pressing station 22 is a sleeve 46 and a core plunger 18 which are independently actuated for pressing workpiecesin the die cells I8. The plungers are preferably fluid operable and may be controlled by any suitable valve means, not shown,

The briquettes or compacts to be worked are indicated at 50 and are placed within the sleeve 32 with the electrically non-conductive spacer discs 52 arranged therebetween. Then, when electrical energy is supplied to the coil 34, the briquettes may be raised to sintering temperature without welding or sticking together.

In order to transfer the compacts to the die cells and to remove the separating discs, there are provided plates 54 and 56, the former of which is reciprocable across the opening of the sleeve 32. The lower plate 55 has an aperture 58 therein of the size to pass a compact but to stop the separating discs. Spaced from the aperture 58 is a second aperture 60 in the plate 56 of a size which will pass the said discs. An apertrue 62 in the plate 54 of the same size as the aperture t!) is adapted for receiving one of the It and around the core plunger 48 by advancing the sleeve 48 against the plunger 42, which is also hollow to receive the end of the core plunger 48. After the forming pressure has been applied for a suiiicient length of time, the plunger 42 is retracted downwardly and the workpiece is ejected by stripping it from the plunger 48 by the sleeve 45.

As a simple means for directing the ejected workpiece to a conveyor or other receiver, there is provided the pivoted chute 64 which pivots into position to receive the eject when the plunger 42 is retracted and which yields before the said plunger when the same is moved into pressing position.

Operation of first embodiment In operation, a number of briquettes or compacts are placed within the sleeve 32 with the spacers 52 therebetween. Electrical energy is supplied to the coil 34 at such a rate that the compacts will be at sintering temperature when they pass from the lower end of the sleeve 32. A reciprocation of the plate 54 feeds a compact into the adjacent die cell I8.

The turret is then indexed to bring the die cell into alignment with the pressing station and a pressing operation takes place, during which the plate 54 is again reciprocated to feed another briquette into the die cell then in alignment with the sleeve 32.

After the pressing is completed, the workpiece is ejected and the turret indexes again to commence a new cycle.

By continuously supplying briquettes and separators to the upper end of the sleeve 32, the

heating coil may be continuously energized in order progressively to heat the compacts to the proper working temperature. The discs between the workpieces prevent the same from sticking together and also assist in trapping gases around i the briquettes in order to prevent oxidation thereof while at elevated temperatures.

Second embodiment In Figs. 7-10, there is shown an apparatus for receiving the compacts or briquettes 10 in a tube 12 and for passing them through a heating chamber, indicated at 74, which is supplied with energy by the induction coil I6.

The compacts are transferred from the sleeve I2 into the chamber 14 and passed through the chamber 74 by a plunger 18 which may be reciprocated by fluid pressure.

The briquettes I0 are ejected from the heating chamber at sintering temperature and are received upon the upper end of a vertically acting transfer plunger 80 which may, like the plunger I8, be reciprocated by fluid pressure.

When the plunger 80 is in its lower position,

the briquette carried thereby is aligned with a die 82 and is transferred therein by the simultaneous actuation of the pressing sleeve 84 and core plunger 88. The briquette, when in the die, is compacted between the sleeve 84 and the hollow plunger 88. The pressing sleeve 84 ami plunger 88 are preferably fluid operable by suitable hydraulic motor means.

After the compact has been pressed into a workpiece, the plunger 88 is retracted and the sleeve 84 is advanced to push the finished workpiece from the dieand onto a conveyor, chute, or other suitable receiver, indicated at 90. At this time, the sleeve 84 moves relative to the plunger 86 to strip the workpiece therefrom.

The heating chamber, transfer plunger, pressing station, and workpiece receiver are all enclosed by a chamber 82 which may be supplied with a reducing atmosphere by the pipe 94 and valve 96. The heated briquette is thus continuously blanketed by a controlled atmosphere, and chemical changes therein of an undesirable nature are prevented.

For actuating the sleeve 84 and plunger 88, there may be provided a motor mechanism, generally indicated at I00, which comprises a cylinder I02 having fluid supplied to one end thereof by the conduit I04 and to the other end thereof by the conduit I06. The sleeve 84 is connected with the piston I08 within the cylinder I02, and the plunger 86 is connected with the piston IIO. When the plungers are in their Fig 7 position, they may be driven forward simultaneously by a supply of pressure fluid through the conduit I04, the conduit I06 being exhausted at this time. The sleeve and plunger move together through out their forward stroke until the piston I08 bottoms. When the sleeve and plunger are in their furthest left hand position, the conduit I 06 communicates with the space between the pistons I08 and IIO by means of the groove II2. Accordingly, when pressure is supplied to the conduit I06 to retract the pistons I08 and I I0, the former is urged leftwardly and the latter rightwardly. When the piston IIO has moved rightwardly a predetermined distance, a lost motion mechanism at I I4 causes it to pick up the piston I08 so that thereafter they move rightwardly together. Simultaneously with the picking up of the piston I08 by the piston IIO, the bypass conduit II6 permits a supply of fluid from the conduit I06 to the left hand side of the piston I08 in order to assist the initiation of the movement thereof.

The rightward movement of the two pistons continues until the piston I I0 bottoms, and thereafter the piston I08 continues rightwardly until it engages the piston I I0, the fluid therebetween being discharged through the check valve II8 which opens from the cylinder I02 into the conduit I04.

Operation of second embodiment In operation, a supply of briquettes is placed in the sleeve I2 and the heating chamber I4, and heat is supplied to the latter by the energization of the coil 16. The briquettes are transferred one at a time from the heating chamber to the pressing station by the plunger 80 to be pressed between the sleeve 84 and the plunger 88.

Briquettes are also supplied to the heating chamber by the plunger I8 from the supply sleeve I2. The energization of the coil I6 may be adjusted so that the briquettes are progressively heated to be at proper sintering temperature when ejected from the heating station.

The above mentioned operations are carried out in a reducing atmosphere supplied to the chamber 92 so that oxidation of the briquettes is prevented and a good quality workpiece results.

It will be apparent that this invention provides means for continuously processing cold briquettes through a heating and a pressing stage into completed workpieces while inhibiting oxidation thereof.

A pressing apparatus embodying the methods of this invention provides for a rapid and economical manner of producing parts from powdered metals.

It will be understood that this invention is susceptible to modification in order to adapt it to diflerent usages and conditions, and, accordthey are passed through said sleeve; electrically non-conductive spacer members between the compacts being heated for preventing the welding together thereof in said sleeve; and feeding means operable in unison with the movement of said die means for ejecting said spacer members while permitting a heated compact to drop into each said die means.

2. In an apparatus for hot pressing compacts of powdered metal into workpieces and having a pressing station; means for supplying hot compacts to said pressing station, comprising a sleeve of dielectric material adapted for passing said compacts; dielectric spacer members within said sleeve between said compacts for preventing fusion of said compacts one with the other and for entrapping gases thereabout; electrically energizable means for progressively heating said compacts to sintering temperature within said sleeve; and means operable for feeding the heated,

compacts one at a time to said pressing station and for ejecting said spacer members.

3. In an apparatus for hot pressing compacts of powdered metal into workpieces and having a pressing station; means for supplying hot compacts to said pressing station, comprising a sleeve of electrically non-conductive material adapted for passing said compacts; electrically non-conductive spacer members within said sleeve between said compacts; an induction coil for progressively heating said compacts to sintering temperature within said sleeve; and means for,

ejecting said spacer members while feeding said compacts one at a time to said pressing station.

4. In an apparatus for hot pressing powdered metal compacts into workpieces and having a pressing station with pressing members; a turret mounting a plurality of dies and operable to suecessively index said dies into said pressing station; means for supplying hot compacts to the die next to be indexed into said pressing station, comprising a vertically arranged passage of electrical insulating material adapted for passing compacts therethrough; electrically non-conductive spacer discs within said passage and between said compacts for preventing the welding together thereof and for entrapping gases thereabout; electrical means for progressively heating the compacts to sintering temperature; and means for ejecting said spacer discs while feeding said compacts to said die.

5. In an apparatus for the hot pressing of powdered metal compacts into workpieces and having a pressing station; a heating station for supplying hot compacts to said pressing station, comprising a vertically arranged sleeve of electrically non-conductive material; an induction coil for heating compacts placed in said sleeve; electrically non-conductive spacer members between the compacts within said sleeve; a first plate adjacent the lower end of said sleeve, having an aperture therein adapted for passing said compacts but for stopping said discs; and a second plate between said first plate and said sleeve, having an aperture therein for receiving said discs, the reciprocation of said second plate being operable to eject a disc and to permit a compact to pass through the aperture of said first plate to said pressing station.

LLOYD D'. RICHARDSON, Sn.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,822,939 Stout Sept. 15, 1931 2,449,365 Bober Sept. 14, 1948 

